Combine the coriander seeds, fennel seeds, cumin, and black peppercorns in a jar, stir well, and set aside.

Bring two cups of water to a simmer. While the water is heating, pound the ginger with the mint to break it up a bit. I use a mortar and pestle, but you can use a wooden spoon or cocktail muddler. When the water is hot, stir in 1 tablespoon of the dry mixture and the ginger-mint mixture. Simmer for 3-5 minutes, remove from heat, cover, and allow to steep for another 3 minutes or so. Place the lemon slices in a strainer, and strain the tea through the lemon into a pot or container.

Makes 2 cups of tea, with enough of the dry tea blend for another 3 pots or so.